DUAL-POLARIZED OPTICALLY CONTROLLED MICROWAVE ANTENNA

• US 20130162490A1
• Filed: 12/07/2012
• Published: 06/27/2013
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: BLECH, Marcel
• Granted Patent: US 9,166,290 B2
• Time in Patent Office: Days
• US Class Current: 343/754
• CPC Class Codes: H01Q 15/002 said selective devices being reconfigurable or tunable, e.g. using switches or diodes
• CPC Class Codes: H01Q 3/2676 Optically controlled phased array
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays

Abstract

An optically controlled microwave antenna that reduces the optical power consumed by the antenna and to enable polarimetric detection an optically controlled microwave antenna comprises an antenna array and a feed for illuminating said antenna array with and/or receiving microwave radiation. The antenna array comprises a plurality of antenna elements each including a waveguide, two optically controllable semiconductor elements arranged within the waveguide in front of the light transmissive portion of the second end portion, a controllable light source arranged at or close to the light transmissive portion of the second end portion for projecting a controlled light beam onto said semiconductor element for controlling its material properties, and a septum arranged within the waveguide in front of the light transmissive portion of the second end portion and separating said waveguide into two waveguide portions.

Claims

1. An optically controlled microwave antenna comprising:

i) an antenna array comprising a plurality of antenna elements, an antenna clement comprising;

a waveguide for guiding microwave radiation at an operating frequency between a first open end portion and a second end portion arranged opposite the first end portion, said second end portion having a light transmissive portion formed in at least a part of the second end portion,

two optically controllable semiconductor elements arranged within the waveguide in front of the light transmissive portion of the second end portion, each or said semiconductor element changing its material properties, in particular its reflectivity of microwave radiation of the operating frequency, under control of incident light,

a controllable light source arranged at or close to the light transmissive portion of the second end portion for projecting a controlled light beam onto said semiconductor element for controlling its material properties, in particular its reflectivity, and

a septum arranged within the waveguidc in front of the light transmissive portion of the second end portion and separating said waveguide into two waveguide portions, wherein within each waveguide portion one of said two semiconductor elements is arranged, and

ii) a feed for illuminating said antenna array with and/or receiving microwave radiation of the operating frequency from said antenna array to transmit and/or receive microwave radiation.

2. The microwave antenna as claimed in claim 1,

wherein said waveguide has a quadratic cross section and said septum is arranged to separate said waveguide into said waveguide portions each having a rectangular cross section, in particular an identical rectangular cross section.

3. The microwave antenna as claimed in claim 1,

wherein said waveguide has a circular or elliptical cross section and said septum is arranged to separate said waveguide into said waveguide portions each having a semi-circular or semi-elliptical cross section, in particular an identical semi-circular or semi-elliptical cross section.

4. The microwave antenna as claimed in claim 1,

wherein said septum comprises a step profile facing into the direction of the first end portion of the waveguide.

5. The microwave antenna as claimed in claim 4,

wherein said septum comprises a step profile having a number of steps in the range from 3 to 10, in particular from 4 to 6.

6. The microwave antenna as claimed in claim 1,

wherein said feed is configured to illuminate said antenna array with and/or to receive microwave radiation from said antenna array, said radiation having one or two different polarizations, in particular having one or two different linear polarizations, circular polarization or elliptical polarizations.

7. The microwave antenna as claimed in claim 6,

further comprising a feed control unit for controlling said feed to illuminate said antenna array with and/or to receive microwave radiation having a predetermined polarization from said antenna array.

8. The microwave antenna as claimed in claim 1,

wherein said semiconductor element is configured to switch its material properties between a conductor and a dielectric causing a phase change of 180°

of the reflected microwave signal in the waveguide.

9. The microwave antenna as claimed in claim 1,

wherein said semiconductor element is formed as a post arranged between, in particular contacting, two opposing sidewalls of the waveguide.

10. The microwave antenna as claimed in claim 9,

wherein the width of said semiconductor element is in the range from 5% to 50%, in particular from 10% to 30%, of the width of the waveguide.

11. The microwave antenna as claimed in claim 9 or 10,

wherein said antenna element further comprises a support element configured to carry said semiconductor element and arranged adjacent to the semiconductor element between said opposing side walls.

12. The microwave antenna as claimed in claim 2,

wherein each waveguide portion has a rectangular cross section having a width in the range from 50% to 90% of the wavelength and a height in the range from 25% to 40% of the wavelength of the microwave radiation of the operating frequency.

13. The microwave antenna as claimed in claim 1,

wherein said semiconductor element is arranged at a distance d₁ from the second end portion of the waveguide of substantially a guided quarter wavelength of the microwave radiation of the operating frequency.

14. The microwave antenna as claimed in claim 1,

wherein said light transmissive portion of the second end portion of a waveguide takes up a portion of 5% to 75%, in particular of 10% to 50%, of the total end area of said second end portion.

15. The microwave antenna as claimed in claim 1,

wherein said antenna element further comprises an antireflection element arranged on one or both sides of said semiconductor element and having a thickness of substantially a quarter wavelength of the microwave radiation of the operating frequency.

16. The microwave antenna as claimed in claim 1,

wherein said antenna element further comprises an aperture element, in particular of a pyramidal form or the form of a horn, arranged in front of the first end portion of the waveguide and having a larger aperture than the first end portion.

17. The microwave antenna as claimed in claim 1,

wherein said antenna element further comprises a waveguide to microstrip transition and a microstrip line, wherein said semiconductor element is arranged in the microstrip line.

18. The microwave antenna as claimed in claim 1,

wherein the semiconductor elements of said antenna array are formed in a grid made of semiconductor material, in particular made of Si, in which holes have been formed, in particular by etching, a post of said semiconductor material remaining between two neighboring holes representing a semiconductor element.

19. The microwave antenna as claimed in claim 18,

wherein the waveguides of said antenna array are formed by an array of tubes having two open ends, said array of tubes being coupled to said grid such that an open end of a tube covers two neighboring holes and a post formed remaining said two neighboring holes.

20. The microwave antenna as claimed in claim 1,

wherein said light source is formed by a laser diode or light emitting diode.

21. The microwave antenna as claimed in claim 1,

wherein the light sources of said antenna array are arranged in a light source matrix, in particular on a light source carrier structure, said light source matrix comprising column and row control lines for individually controlling said light sources.

22. The microwave antenna as claimed in claim 1,

further comprising a control circuit comprising a control unit per light source or group of light sources for controlling the light sources of said antenna array, a control unit comprising a switchable element coupled in parallel to said light source and a switching clement for switching said switchable element on an off under control of a switching element control signal.

23. The microwave antenna as claimed in claim 22,

wherein said switchable element is formed by a thyristor or a triac, in particular a photo thyristor, and wherein said switching element is formed by a diode, in particular an IR diode.

24. The microwave antenna as claimed in claims 21 and 22,

wherein said control circuit further comprises a line switch per column or row of said light source matrix for switching a line current provided to a column or row of light sources coupled in series on and off under control of a line control signal.

25. The microwave antenna as claimed in claim 1,

wherein said light transmissive portion is an opening.

26. The microwave antenna as claimed in claim 1,

wherein said light transmissive portion comprises an indium tin oxide layer arranged in front of said light source.

27. An antenna array, in particular for use in an optically controlled antenna as claimed in claim 1, comprising a plurality of antenna elements, an antenna element comprising:

a waveguide for guiding microwave radiation at an operating frequency between a first open end portion and a second end portion arranged opposite the first end portion, said second end portion having a light transmissive portion formed in at least a part of the second end portion,

two optically controllable semiconductor elements arranged within the waveguide in front of the light transmissive portion of the second end portion, each of said semiconductor element changing its material properties, in particular its reflectivity of microwave radiation of the operating frequency, under control of incident light,

a controllable light source arranged at or close to the light transmissive portion of the second end portion for projecting a controlled light beam onto said semiconductor element for controlling its material properties, in particular its reflectivity, and

a septum arranged within the waveguide in front of the light transmissive portion of the second end portion and separating said waveguide into two waveguide portions, wherein within each waveguide portion one of said two semiconductor elements is arranged.